they want something like 35-40 percent support, which in their book is "plenty."
I personally doubt if the White House staff cares if they even get that much. President Bush will just order the strikes and dare anyone to stop him.
Any attempt to take action in congress will be blocked when Republicans fillibuster the bills in the Senate (100% loyalty to Bush, again).
At this stage I believe that George W. Bush has decided to start a war with Iran, just as he did with Iraq. Nothing will stop Bush's war in Iran any more. Nothing.
So, considering that absolutely no law will make it past a Republican fillibustered Senate, the only option left is for Democrats to refuse to fund any more war actions fro Bush. Democrats can take this action since not passing bills is within the math.
What may not be possible is sufficient testicular fortitude for Democrats to actually take such an action. To date that has not been demonstrated, but I can only hope, and write my reps in Congress to take such a stance (two are Democrats and therefore reachable. Senator Specter will, of course make public pronouncements of independence, but actually vote exactly as the White House wants: He rolls over faster than a DC Madam.)